Humeral implant anchor system

ABSTRACT

A stemless humeral shoulder assembly having a base member and an anchor advanceable into the base member. The base member can include a distal end that can be embedded in bone and a proximal end that can be disposed at a bone surface. The base member can also have a plurality of spaced apart arms projecting from the proximal end to the distal end. The anchor can project circumferentially into the arms and into a space between the arms. When the anchor is advanced into the base member, the anchor can be exposed between the arms. A recess can project distally from a proximal end of the anchor to within the base member. The recess can receive a mounting member of an anatomical or reverse joint interface.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 16/580,367, filed Sep. 24, 2019, which is continuation of U.S.patent application Ser. No. 15/192,628, filed Jun. 24, 2016, now U.S.Pat. No. 10,456,264, which is a continuation-in-part of PCT ApplicationNo. PCT/US2014/072443, filed Dec. 26, 2014, which claims to the prioritybenefit of U.S. Provisional Application No. 61/931,500, filed Jan. 24,2014, both of which are hereby incorporated by reference in theirentirety herein. U.S. patent application Ser. No. 15/192,628 also claimsthe priority benefit of U.S. Provisional Application No. 62/192,797,filed Jul. 15, 2015, which is hereby incorporated by reference in itsentirety herein.

BACKGROUND Field

The present disclosure relates to stemmed and stemless humeralcomponents of a shoulder joint prosthesis.

Description of the Related Art

In a shoulder joint, the head of the humerus interacts with the glenoidcavity of the scapula in a manner similar to a “ball and socket” joint.Over time, it may become necessary to replace the shoulder joint with aprosthetic shoulder joint including a humeral component.

Traditionally, the humeral component is a single body implant having ahumeral head and a stem. The stem is configured to be inserted into anintramedullary canal of the humerus. In certain cases, insertion of thestem disadvantageously requires bone to be removed to fit the stem tothe canal due to patient-to-patient anatomical variation. Anotherdisadvantage of this approach is that integration of the stem into thebone through a natural process of bone ingrowth can make it difficult toremove the humeral component if it becomes necessary to replace thehumeral component with another device. Even when no removal wasexpected, this approach had the disadvantage of only achieving implantsecurity after sufficient time had passed to allow for sufficient boneingrowth.

A stemless humeral component may be used to address some of thedisadvantages of conventional humeral components. Stemless humeralcomponents can decrease the amount of bone loss in preparing the humerusto receive the component and decrease the complexity of the jointreplacement procedure.

Stemless humeral component designs can be more challenging to secure tothe humerus. Conventional stemless designs rely on bone ingrowth forstrength. While such designs perform well over time, there is a risk inthe early days and weeks after surgery where such ingrowth has not yetoccurred that the stem and stemless humeral component will be dislodgedfrom the humerus. Dislodgement may also occur due to excessive wear,forces applied thereto during a revision surgery or other high loadconditions.

SUMMARY

Accordingly, there is a need for a stemless humeral component orprosthesis designed to preserve bone in initial implantation whileenhancing initial pull-out resistance. Preferably enhanced initialdislodgement resistance will also provide excellent long term fixation.

The present disclosure relates to various embodiments of a stemlesshumeral shoulder assembly that can minimize bone loss and provideexcellent initial pull-out resistance and long term fixation.Advantageously, the humeral shoulder assemblies described herein provideadequate compression, increase rotational and longitudinal stability,and encourage bone ingrowth.

Certain aspects of the disclosure are directed toward a prosthesismounting system having a base member adapted to be driven into bone. Thebase member can include a central portion having a lumen extending alonga longitudinal axis and a peripheral portion connected to the centralportion. Further, the prosthetic mounting system can include an anchorhaving an inner passage sized to be advanced along the longitudinal axisof the base member. The anchor can have at least one thread surroundingthe inner passage. When the anchor is coupled with the base member, thethread extends outward of the central portion of the base member.

In one embodiment, a stemless humeral shoulder assembly is provided. Theassembly includes a base member and an anchor member. The base memberhas a distal end that can be embedded in bone and a proximal end thatcan be disposed at a bone surface. The base member has a plurality ofspaced apart arms projecting from the proximal end to the distal end.The anchor member is advanceable into the base member to a positiondisposed within the arms. The anchor member is configured to projectcircumferentially into the arms and into a space between the arms. Theanchor member is exposed between the arms when advanced into the basemember. The assembly includes a recess projecting distally from aproximal end of the anchor member to within the base member. The recessis configured to receive a mounting member of an anatomical or reversejoint interface.

In another embodiment, a humeral shoulder assembly is provided thatincludes a stem and an anchor. The stem has a proximal region to bedisposed in the metaphysis of a humerus, a distal end configured to bedisposed in a canal of a humerus and a proximal end. The proximal end isto be disposed at a bone surface. The proximal region of the stem has aplurality of spaced apart projections disposed adjacent to the proximalend. The anchor is advanceable into the stem to a position disposedwithin the projections. The anchor is configured to projectcircumferentially into the projections and into a space between theprojections. The anchor is exposed between the projections when advancedinto the stem. The humeral shoulder assembly includes a recess thatprojects distally from a proximal end of the anchor to within the stem.The recess is configured to couple with an articular component.

In another embodiment, a prosthesis mounting system is provided thatincludes a stem and an anchor. The stem is adapted to be driven intobone. The stem has a central portion that includes a lumen. The lumenextends along a longitudinal axis. A peripheral portion of the stem isconnected to the central portion. The stem extends distally of thecentral portion. The anchor has an inner passage sized to be advancedalong the longitudinal axis. The anchor having at least one threadsurrounding the inner passage. When the anchor is coupled with aproximal portion of the stem, the thread extends outward of the centralportion of the base member.

Certain aspects of the disclosure are directed toward methods fortreating a shoulder joint. The methods can include accessing a humeralhead, resecting the humeral head, driving a base member into the humeralhead, and advancing an anchor member into the base member. When theanchor member is advanced into the base member, a lateral projection ofthe anchor member can be disposed through the base member and can beembedded in bone adjacent to the base member. In certain aspects, themethods can also include securing a joint interface to the base memberand/or the anchor member.

In another method for treating a shoulder joint, an end portion of ahumerus is accessed. A stem is driven into the end portion of thehumerus such that a portion of the stem extends into a canal of thehumerus. An anchor member is advanced into the stem such that a lateralprojection thereof is disposed through the stem and is embedded in boneadjacent to the stem. A joint interface is secured to the stem and/orthe anchor member.

As described above, in certain aspects the stemless humeral componentcan be modular to provide more options for the surgeon during a revisionsurgery. For example, the modular humeral component can include astemless fixation component adapted to be secured in the head of thehumerus and a spherical head removably attached to the fixationcomponent. During the revision surgery, the modular approach can make iteasier to convert an anatomic shoulder prosthesis to a reverse shoulderprosthesis.

In any of the above-mentioned aspects, the anchor member can include ahelical structure advanceable to engage corresponding surfaces of thearms. In certain aspects, the anchor can include a cylindrical sleeveand the helical structure can include at least one thread (e.g., onethread, two threads, three threads, or four threads) projectinglaterally therefrom.

Any feature, structure, or step disclosed herein can be replaced with orcombined with any other feature, structure, or step disclosed herein, oromitted. Further, for purposes of summarizing the disclosure, certainaspects, advantages, and features of the inventions have been describedherein. It is to be understood that not necessarily any or all suchadvantages are achieved in accordance with any particular embodiment ofthe inventions disclosed herein. No aspects of this disclosure areessential or indispensable.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages are described belowwith reference to the drawings, which are intended to illustrate but notto limit the inventions. In the drawings, like reference charactersdenote corresponding features consistently throughout similarembodiments. The following is a brief description of each of thedrawings.

FIG. 1A is a perspective view of one embodiment of a stemless humeralshoulder assembly shown mounted in a humerus;

FIG. 1B is a cross-sectional view of FIG. 1A, showing the stemlesshumeral shoulder assembly disposed in the humeral head;

FIG. 2 is a perspective view of the stemless humeral shoulder assemblyof FIGS. 1A and 1B;

FIG. 3 is an exploded view of the stemless humeral shoulder assembly ofFIG. 2;

FIG. 4 is a top view of the base member of the shoulder assembly of FIG.2;

FIG. 5 is a first side view the base member of FIG. 4;

FIG. 6 is a second side view of the base member of FIG. 4;

FIG. 6A is a cross-section of the base member shown in FIG. 6 throughline 6A-6A in FIG. 4;

FIG. 7 is a top perspective view of an anchor member of the shoulderassembly of FIG. 2;

FIG. 8 is a side view of the anchor member of FIG. 7;

FIG. 9 is a bottom view of the anchor member of FIG. 7;

FIGS. 10A-10H illustrate steps of various methods of implantation of thestemless humeral shoulder assembly of FIG. 2;

FIG. 11 is a top perspective view of another embodiment of a stemlesshumeral shoulder assembly;

FIG. 12 is a top perspective view of a base member of the stemlesshumeral shoulder assembly of FIG. 11;

FIG. 13 is a top view of the base member of FIG. 12;

FIG. 13A is a side view of the base member of FIG. 12;

FIG. 14 is a top perspective view of an anchor member of the stemlesshumeral shoulder assembly of FIG. 11;

FIG. 15 is a top view of the anchor member of FIG. 14;

FIGS. 16A-16C illustrate steps of various methods of implantation of thestemless humeral shoulder assembly of FIG. 11;

FIG. 17 is a top perspective view of another embodiment of a stemlesshumeral shoulder assembly;

FIG. 18 is a top perspective view of a base member of the stemlesshumeral shoulder assembly of FIG. 17;

FIG. 19 is a top view of the base member of FIG. 18;

FIG. 20 is a side view of the base member of FIG. 18;

FIG. 21 is a bottom view of the base member of FIG. 18;

FIG. 22 is a cross-sectional view of the base member of FIG. 19 alongline 22-22;

FIG. 23 is a top perspective view of an anchor member of the stemlesshumeral shoulder assembly of FIG. 17;

FIGS. 24A-24B illustrate tool and component combinations that can beprovided in various methods of implantation of the stemless humeralshoulder assembly of FIG. 17;

FIG. 25 illustrates an adaptor or centering pin that can be used toalign a driver with a base member, as discussed herein;

FIG. 26 illustrates the performance of various embodiments of stemlesshumeral shoulder assemblies;

FIG. 27 is a cross-sectional view of another embodiment of a shoulderassembly having a locking device disposed between a base member and ananchor member thereof to reduce or eliminate disengagement of the anchormember from the base member;

FIG. 27A is an enlarged view of the locking device shown in FIG. 27taken through line 27A-27A;

FIG. 28 is a top perspective view of an anchor member assembly of theshoulder assembly of FIG. 27;

FIG. 29 is a side view of a shoulder assembly having another embodimentof a locking device;

FIG. 30 is a side view of an anchor member of the shoulder assembly ofFIG. 29;

FIG. 31 is a top view of a shoulder assembly having another embodimentof a locking device; and

FIG. 32 is a bottom perspective view of a tool for actuating a lockingstructure of the locking device of the shoulder assembly of FIG. 31 froma disengaged configuration to an engaged configuration.

FIGS. 33 and 34 are a top perspective and side views of a humeralimplant including the anchor member.

FIG. 35 is a side view of a stem of the humeral implant of FIG. 33without anchor member.

FIG. 36 is a view showing the components of a stemless humeral implanthaving one or more surfaces formed by additive manufacturing.

FIG. 37 is a top perspective view of another embodiment of a humeralimplant with a stem, at least a portion of the implant being formed byadditive manufacturing.

DETAILED DESCRIPTION

While the present description sets forth specific details of variousembodiments, it will be appreciated that the description is illustrativeonly and should not be construed in any way as limiting. Furthermore,various applications of such embodiments and modifications thereto,which may occur to those who are skilled in the art, are alsoencompassed by the general concepts described herein. Each and everyfeature described herein, and each and every combination of two or moreof such features, is included within the scope of the present inventionprovided that the features included in such a combination are notmutually inconsistent.

FIG. 1A shows a humeral shoulder assembly 100 that has been implanted inan exposed face F of a humerus H. The assembly 100 has a recess 104 inwhich further components of a prosthetic shoulder joint can be secured.The configuration of the assembly including the recess 104 enable thehumerus H and a corresponding scapula to be fitted with either ananatomical shoulder or a reverse shoulder configuration either initiallyor as part of a revision procedure. FIG. 1B shows that in certainapplications, the shoulder assembly 100 can be fully retained within ahead h of the humerus H. In other words, the distal-most portion of theassembly 100 is disposed in the humeral head h. The assembly 100 doesnot have members that protrude beyond the head h into the intramedullarycanal. This arrangement is less invasive and simplifies the procedurecompared to a procedure involving a humeral component with a stem, asdiscussed elsewhere herein.

FIGS. 2-9 elaborate on advantageous structures and variations of theshoulder assembly 100 that can be employed in the stemless approach ofFIGS. 1A-1B. Methods of using the shoulder assembly 100 are discussedbelow in connection with FIGS. 10A-10H. Shoulder assemblies capable ofbeing at least partly delivered over a guide wire are discussed below inconnection with FIGS. 11-16C. FIGS. 17-24B illustrate shoulderassemblies where a joint interface mounting platform or recess isdisposed on a base member and an anchor member is provided primarily orsolely for bone securement function. FIG. 25 shows an adaptor that canbe used in connection with several embodiments and methods of applyingshoulder assemblies. FIG. 26 illustrates the performance of certainembodiments compared to a prior art design. While incrementaldifferences in these embodiments and methods are discussed below, it isto be understood that features of each embodiment can be combined withfeatures of the other embodiments, as appropriate.

I. Assemblies Having Reinforced Bone Engaging Anchor Members

FIGS. 2 and 3 show more detail of components of the shoulder assembly100 that among other features and advantages provides an anchor memberwith an inwardly positioned cylindrical member that reinforces outwardlypositioned helical structures as discussed below.

The assembly 100 has a base member 108 and an anchor member 112. FIG. 3shows that the base member 108 and anchor member 112 are separablecomponents that can be applied to the patient separately, e.g.,assembled in multiple steps within the bone as discussed below. The basemember 108 has a distal end 120 and a proximal end 124. The distal end120 is configured to be embedded in the head of a humerus. The proximalend 124 is configured to be disposed adjacent to a face of the humerusor another bone surface. The base member 108 has a plurality of spacedapart arms 128 projecting from the proximal end 124 to the distal end120. The base member 108 also has a central portion, e.g., a cylindricalmember 130, that forms part of the recess 104, as discussed in moredetail below. In the illustrated embodiment, the arms 128 are equallyspaced about the cylindrical member 130. The arms 128 can be spacedapart by about 120 degrees. The base member 108 and the other basemembers discussed below can have three arms. The base member 108 and theother base members discussed below can have one or a plurality of arms128. In various embodiments, the base member 108 and the other basemembers discussed below can have two, three, four, five, or six arms.The arms 128 preferably are thin in the circumferential direction suchthat large gaps are provided between the arms.

FIGS. 3 and 4 show the proximal end 124 of the base member 108 in moredetail. In particular, the proximal end 124 can include a peripheralmember 140 disposed about the outer periphery of the proximal end 124.The peripheral member 140 can be coupled with proximal ends 144 of thearms 128 (see FIGS. 5-6A) to provide a unitary structure. In oneembodiment, the peripheral member 140 comprises an annular structure 145that is tapered such that a convex surface 146 is provided betweenproximal and distal portions of the peripheral member 140. The convexsurface 146 extends from a bone engaging side of the peripheral member140 to a proximal side of the peripheral member 140. The proximal sideof the peripheral member 140 is disposed adjacent to but may be spacedfrom another joint component, such as a portion of an assembly includingan anatomical or reverse shoulder joint humeral interface.

In one embodiment, the proximal end 124 can include a plurality of guidemembers 148 that can be coupled with the peripheral member 140. Theguide members 148 can include plate-like projections extending radiallyinwardly from an arcuate segment of the peripheral member 140. The guidemembers 148 can be coupled with, attached to or a monolithic extensionof an inner edge of the peripheral member 140. In one embodiment, thebase member 108 includes three guide members 148. The guide members 148can include an angled or lead surface 152 that is angled relative to atransverse plane of the proximal end 124. As used in this context, atransverse plane of the proximal end 124 is a plane that extendsperpendicular to a longitudinal axis A (see FIGS. 5 and 6A) of thecylindrical member 130. The angle of the lead surface 152 is selected tomatch the angle of a distal face of a helical structure of the anchormember 112 as discussed further below in connection with FIGS. 6A and 8.

In one embodiment, each of the guide members 148 includes a flat surface156. Each of the flat surfaces 156 can be disposed on a transverse planeof the proximal end 124. The flat surfaces 156 can extend between anouter portion 160 coupled with the peripheral member 140 and an innerportion 168 disposed adjacent to the cylindrical member 130. In theillustrated embodiment, each inner portion 168 of three guide members148 is spaced from the cylindrical member 130 by a corresponding gap172. The gaps 172 partly define an annular volume (projecting distallyinto the page in FIG. 4) in which a cylindrical portion of the anchormember can be disposed, as discussed further below.

FIG. 3 shows that the flat surface 156 can be disposed at an elevationdistal of (or below) the proximal-most aspect of the peripheral member140. The distance between the proximal-most aspect of the peripheralmember 140 and the flat surface 156 can provide a space into which atleast a portion of the anchor member 112 can be recessed. In oneembodiment, a proximal end 180 of the cylindrical member 130 is disposedat about the same elevation of the proximal-most aspect of theperipheral member 140. In some embodiments, an outside surface of thecylindrical member 130 and an inside surface of the peripheral member140 define side surfaces of an annular space into which a proximalportion of the anchor member 112 can be received. FIG. 2 shows that theannular space bounded by the outside surface of the cylindrical member130 and the inside surface of the peripheral member 140 provides asubstantially flush, e.g., stepless, profile or transition from theinner and proximal-most aspect of the peripheral member 140 to an outerperiphery 182A of the anchor member 112 and from an inner periphery 182Bof the anchor member to the proximal end 180 of the cylindrical member130. The flush profile enables other components of a shoulder joint tobe drawn down adjacent to but preferably spaced from the assembly 100.

FIG. 4 shows that the guide members 148 generally are spaced apart byarcuate openings 192. The openings 192 extend from a lower end of one ofthe angled surfaces 152 to an end of an adjacent guide member 148. Asdiscussed further below, the openings 192 permit laterally extendingportions of the anchor member 112 to be advanced into the base member108. In certain embodiments, the laterally extending projections includeone or more, e.g., three, threads that can be advanced through theopenings to engage with the base member 108 at a position distal of theguide members 148. FIG. 4 shows that the arms 128 are disposed distal ofbut accessible through the openings 192. The arms 128 are located at acircumferential position between the angled surface 152 of a first guidemember 148 and a non-angled surface of a second guide member 148, wherethe second guide member is adjacent to the first guide member.Preferably, the circumferential position of the arms 128 is closer tothe circumferential position of the non-angled surface of the secondguide member 148 as shown. In this context, the circumferential positionis determined by projecting these structures to the plane upon which thenon-angled surface 148 is disposed. FIG. 6A shows that a proximalportion of the arms 128 is located distal of the distal-most aspect ofthe angled surface 152.

FIG. 6A shows one of the arms 128 in more detail. In some embodiments,the arms 128 are each identical. In other embodiments, the arms differfrom each other. For example, in the single thread configurations ofFIGS. 11 and 17 the arms differ from each other in having slots advanceddistally from a first arm to a next arm in the direction of rotation ofan anchor member to accommodate the path of the helical member orthread, as discussed below in connection with those embodiments. Thearms 128 have a plurality of slots 202, e.g., three slots disposedbetween proximal and distal ends thereof. FIG. 6A shows that theproximal-most slot 202 can be different from the two slots 202 disposeddistal thereof in that the proximal-most slot 202 is bounded by a lowersurface 218A discussed below but not by a corresponding upper edgeformed in the arm 128. As noted above, the arm 128 is coupled with theperipheral member 140 at a proximal end 144 of the arm 128. In oneembodiment, a unitary structure is provided. In such a structure, acontinuous structure can be provided from within the peripheral member140 to within a proximal portion of the arm 128 so that there are nowelds or joining lines or boundaries in this area. Such an arrangementsimplifies the structure and eliminates potential areas forconcentration of stress and potentially failure.

An outer edge 210 of the arms 128 provides a continuously arcuatesloping surface in one embodiment. The sloping surface can facilitateinsertion of the base member 108 into an exposed humeral face F asdiscussed above and further below in connection with FIGS. 10A-10H. Aninner edge 214 of the arm 128 can include one or a plurality of, e.g.,three, laterally extending faces or surfaces 218A, 218B, 218C.

The angle of the surfaces 152, 218A, 218B, 218C can be configured tofacilitate advancement of a lateral extent of the anchor member 112along a helical path. For example, initial advancement of a lateralportion of the anchor member 112 can cause a leading edge surface of theanchor member 112 to slide along the surface 152 shown in FIG. 6A.Continued advancement can cause the leading edge surface of the anchormember 112 to approach and then slide across the surface 218A shown inFIG. 6A. Continued advancement can cause the leading edge surface of theanchor member 112 to approach and then slide across a surface 218B of anarm 128 disposed adjacent to and on a first side of the arm 128 shown inFIG. 6A. Continued advancement can cause the leading edge surface of theanchor member 112 to approach and then slide across a surface 218C of anarm 128 disposed adjacent to and on a second side of the arm 128 shownin FIG. 6A. Once the anchor member 112 slides across the surface 218C ofeach arm 128, the anchor member 112 can continue to rotate an additional5-15 degrees to further compress the entire construct into the bones.Advancement is complete when a proximal face of the threads 340 (seeFIG. 8) contacts an upper surface 222B, 222C of the slots 202 (see FIG.6A).

At least some of the surfaces 218A, 218B, 218C can be disposed inlaterally projecting recesses or channels of the arms 128. For example,the surface 218B extends laterally outwardly from the inner edge 214 ofthe arms 128. A corresponding surface 222B can extend outwardly from theinner edge 214 adjacent to the surface 218B. The surfaces 218B, 222B canbe substantially parallel along their length. The surfaces 218B, 222Bcan be spaced apart by a short distal-proximal distance. The shortdistal-proximal distance can be about the same as the thickness oflateral protrusions (e.g., threads) of the anchor member 112 discussedbelow. In these embodiments both of the surfaces 218B, 222B play a rolein guiding the advancement of the anchor member 112. The face 222B canhave an angled surface similar to that of the surface 218B. For example,the angle of the face 222B can be the same angle as that of the face218B.

In one embodiment, each of the faces 218A, 218B, 218C has a length asmeasured radially away from the axis A that differs from the length ofthe other faces. The distal-most face 218C can have the shortest length.The proximal-most face 218A can have the longest length. A face 218Bdisposed between the distal- and proximal-most faces 218C, 218A can havean intermediate length. These lengths can correspond to the taperedprofile of the base member 108, e.g., with the arms 128 having agenerally convex shape from proximal to distal as viewed from the side.The lengths of the faces 218A, 218B, 218C can correspond to the profileof the lateral projection of the anchor member 112, which is someembodiments may be tapered.

In one embodiment, the proximal-most face 218A does not have acorresponding face on the arm 128 disposed proximal thereof. A lowersurface of the guide member 148 disposed adjacent to but clockwise ofthe arm 128 can abut a proximal side of a thread while a distal side ofthe thread advances along the face 218A. In this sense, each of thefaces 218A, 218B, 218C has a corresponding surface that together guide athread of the anchor member 112 as discussed further below.

In the embodiment of FIGS. 1-10H, each arm has a plurality of, e.g.,three faces 218A, 218B, 218C. The face 218A of each of the arms 128 isdisposed at the same elevation as the corresponding face 218A ofadjacent arms 128. The face 218B of each of the arms 128 is disposed atthe same elevation as the corresponding face 218B of adjacent arms 128.The face 218C of each of the arms 128 is disposed at the same elevationas the corresponding face 218C of adjacent arms 128. This constructiondefines a plurality of helical paths on the base 108 for guiding helicalmembers, as appropriate for certain embodiments. Other embodiments havedifferent helical paths, such as a single path as discussed below inconnection with the embodiments of FIGS. 11 and 17. Rather, a pluralityof spaced-apart surfaces reside on and/or define the helical path. Inone right-hand configuration, a first helical path is defined by a face218A of a first arm 128, a face 218B of a second arm 128 adjacent to butdisposed clockwise of (as defined above) the first arm, and a face 218Cof a third arm 128 adjacent to but disposed counter-clockwise of (asdefined above) the first arm. In one embodiment, the first helical pathalso includes the lead surface 152 disposed above and circumferentiallybetween the first and third arms 128. A second helical path can extendfrom a surface 152 to the second arm 128 to a face 218C of the first arm128. A third helical path can extend from a surface 152 of the third arm128 to a face 218C of the second arm 128. Each of the surfaces on thehelical paths can have substantially the same angle relative to atransverse plane of the base 108. In some embodiments, the angle of thefaces 218A, 218B, 218C can be different.

In other embodiments of the base member 108, three left-handed helicalpaths can be provided, each one commencing with an oppositely orientedsurface similar to the surfaces 152 and traversing counter-clockwise toa face 218A below and on the arm 128 immediately counter-clockwise ofthe oppositely oriented surface, then to the face 218B on the next arm128 and then to the face 218C on the next arm 128. In this context, the“next arm 128” is the arm circumferentially spaced from and immediatelycounter-clockwise of the arm from which the path extends.

Unlike a conventional mating screw structure, only very small segmentsof the helical path involve contact between the faces 218A, 218B, 218Cand a mating structure. This arrangement enhances the surface area ofthe anchor thread contacting bone when the assembly 100 is disposed inthe bone.

FIG. 5 shows that a gap 232A is provided between the inner edge 214 andthe cylindrical member 130 below the face 218A. A gap 232B is providedbetween the inner edge 214 and the cylindrical member 130 below the face218B. A gap 232C is provided between the inner edge 214 and thecylindrical member 130 below the face 218C. The gap 232C issubstantially the same width as the gaps 232A, 232B. In one embodiment,the gaps 232A, 232B, 232C are substantially the same as the gap 172. Thegaps 172, 232A, 232B, 232C define part of a cylindrical space configuredto receive part of the anchor member 112 as discussed further below. Thegap 232C enables a distal portion of the anchor member 112 to beadvanced distal of the face 218C.

FIG. 6A shows that in some embodiments, the cylindrical member 130 has athreaded recess 250 formed in a lower portion thereof. The threadedrecess 250 enables a component to be advanced into engagement with thebase member 108. The component can be another component of a prostheticjoint or can be a tool used in placement of one or more components ofthe shoulder assembly 100. The recess 250 can engage a guide tool 432(see FIG. 25) in one technique, discussed in more detail in connectionwith FIG. 10F.

FIGS. 2 and 7-9 illustrate features of the anchor member 112 which, asdiscussed above, is advanceable into the base member 108 to a positiondisposed within the arms 128. The anchor member 112 includes a proximalface 300, a helical structure 304 disposed distally of the proximal face300, and a cylindrical sleeve 308 configured to be disposed around therecess 104. In some embodiments, the sleeve 308 is configured to beadvanced over and receive the cylindrical member 130 as discussedfurther below.

The proximal face 300 comprises the proximal side of a disc structure312 disposed at the proximal end of the anchor member 112. The discstructure 312 is configured to be disposed in a space partly bounded bythe flat surfaces 156, the inner face of the peripheral member 140, andthe outer face at the proximal end 180 of the cylinder member 130 of thebase member 108 (see FIG. 3). The disc structure 312 can have athickness (proximal-to-distal distance) substantially the same as thedistance from the flat surfaces 156 to the proximal most aspect of theperipheral member 140. The anchor member 112 is configured such thatregions 320 (FIG. 9) of the distal surface of the disc structure 312 areadvanced into a position to abut the flat surfaces 156 of the basemember 108 when the shoulder assembly 100 is assembled.

FIGS. 8 and 9 show the helical structure 304 in more detail. In oneembodiment, the helical structure 304 includes three spaced aparthelical protrusions 332A, 332B, 332C. In this embodiment, the anchormember 112 has a triple lead configuration. Other embodiments can have asingle lead (as in the embodiments discussed in connection with FIGS. 11and 17 below), a double lead, or a quadruple lead configuration. Distalends of the three helical protrusions 332A, 332B, 332C can be seen inFIG. 9. Each of these helical protrusions 332A, 332B, 332C hasprogressively larger diameter from a distal end to a proximal endthereof in the illustrated embodiment. The larger size toward theproximal end enables the helical protrusions to project fartherlaterally into the faces 218A, 218B, 218C of the arms 128. The smallersize toward the distal end enables the disruption of bone toward thedistal end to be minimized. The helical protrusions can be threads insome embodiment.

FIG. 8 shows distal and proximal faces 336, 340 of one of the helicalprotrusions. The distal face 336 is configured to be advanced along oneor guided by one of the helical paths described above. The distal face336 is angled relative to a transverse (e.g., perpendicular)cross-sectional plane of the anchor member 112, which angle may beselected to match the lead surface 152, as discussed above. For example,the distal face 336 can slide along the lead surface 152, one of thefaces 218A, one of the faces 218B, and one of the faces 218C. Theproximal face 340 can slide along or be guided by the surface 228B (FIG.6A) or another distally-oriented face disposed in one of the arms 128 oron a lower surface of the guide member 148.

FIG. 8 shows that a spiral or helical surface 342 extends betweenadjacent helical protrusions 332A, 332B, 332C. The spiral surface 342can extend from the base of a distal surface 336 of the helicalprotrusion 332B to the base of the proximal surface of the helicalprotrusion 332C. The spiral surface 342 has a proximal to distaldimension that is about the same as the proximal-distal dimension of theside surface 214 between the surfaces 218A, 228B (See FIG. 6A). Theproximal to distal dimension of the spiral surface 342 is about 50%larger than and in some cases twice as large as the proximal to distaldimension of the helical protrusions 332A, 332B, 332C.

FIG. 2 shows that the anchor member 112 projects into the arms 128 andinto a space between the arms when the anchor member and the base memberare assembled. The anchor member 112 is exposed between the arms 128when advanced into the base member 108. More specifically, a pluralityof elongate segments 352 of the helical protrusions 332A, 332B, 332C arenot covered by the faces 218A, 218B, 218C, 222B of the arms 128 butrather are located in an open area between the arms. The exposedsegments 352 create areas of engagement with the bone that vastlyincrease the initial pull-out force of the assembly 100 when initiallyplaced. This improved initial pullout force greatly reduces the chanceof dislodgement, as discussed below in connection with FIG. 26.

Some additional unique features of the assembly 100 include helicalsurfaces in the anchor member 112 that mate only in very small andspaced apart areas of the base member 108 while exposing a majority ofthe helical surface to allow the exposed areas to be disposed directlyin the bone for direct contact therewith. In some embodiments, a portionof the helical surface is disposed within the arms 128 and not exposedbut a majority of the helical surface is exposed to be embedded in bone.The percentage of the surface area of the exposed segments 352 to thetotal area of the helical protrusions 332A, 332B, 332C is between about80 and 98% in some embodiments. The percentage of the area of theexposed segments 352 to the total area of the helical protrusions 332A,332B, 332C is between about 85 and 95% in some embodiments. Thepercentage of the area of the exposed segments 352 to the total area ofthe helical protrusions 332A, 332B, 332C is about 91% in someembodiments. Similarly, the ratio of the length of the exposed segments352 to the total length of the helical protrusions 332A, 332B, 332C isbetween about 0.8 and about 0.98, e.g., between about 0.85 and about0.95, e.g., about 0.9 in various embodiments. It may be desirable tofurther enhance engagement of the assembly 100 and other assembliesherein by increasing the ratios and percentages discussed in thissection. Higher percentages and ratios can be provided by decreasing thedistance between threads such that each thread has more turns. Thepercentage and ratios discussed in this passage are also applicable tothe other embodiments discussed below.

Also, the structure provided herein enables the threads to extend alarge distance from the center of the recess 104. For example, thelateral extent, e.g., radius of the helical protrusions 332A, 332B, 332Ccan be at least 50% of the lateral extent, e.g., radius of theperipheral member 140, for example, at least about 50% and/or less thanor equal to about 75%. In some embodiments, the lateral extent of atleast one of the helical protrusions 332A, 332B, 332C can be at leastabout 50%, such as between about 50% and about 55%, of the diameter ofthe peripheral member 140. In some embodiments, the lateral extent of atleast one of the helical protrusions 332A, 332B, 333C can be at leastabout 60%, such as between about 60% and about 65%, of the diameter ofthe peripheral member 140. In some embodiments, the lateral extent ofthe helical protrusions 332A, 332B, 333C can be at least about 70%, suchas between about 70% and about 75%, of the diameter of the peripheralmember 140. In certain embodiments, as shown in FIG. 8, the diameter ofeach of the helical protrusions 332A, 332B, 332C can vary from theproximal face 300 to the distal end 310 of the anchor 112. For example,the diameter of a portion of the helical protrusions 332A, 332B, 332Cnear the proximal face 300 can be greater than the diameter of a portionof the helical protrusions 332A, 332B, 332C near the distal end 310. Thepercentage can be measured against any portion of the protrusions 332A,332B, 332C. In some embodiments, the lateral extent of the helicalprotrusion 332C can be between about 50% and 55% of the diameter of theperipheral member 140, while the lateral extent of the helicalprotrusion 332A can be between about 70% and 75% of the diameter of theperipheral member 140.

FIG. 7 shows that the proximal face 300 of the anchor member 112 caninclude a driver interface 364 to facilitate advancing the anchor member112 into the base member 108. The driver interface 364 can take anysuitable form, for example, as three spaced apart recesses. The recessescan be cylindrical recesses extending into the disc member 312.

FIGS. 10A-10H illustrate methods of implanting the humeral shoulderassembly 100 into the humerus H. Prior to the step illustrated by FIG.10A, surgical access has been provided to the humerus H and the humerushas been prepared. Preparing the humerus H can include cutting off ajoint-facing portion of the humeral head h. The joint facing portion canbe further prepared, for example by providing a countersunk region CS inthe exposed face F. The countersunk region CS enhances a low profileapplication of the assembly 100 as discussed further below. A pin 400 isplaced in a central region of the countersunk region CS. FIG. 10B showsthat the pin 400 may be used to guide a reamer to create a well at thebase of the pin. FIG. 10C shows the well having received a tool 404 thathas been advanced into the face F to modify the well to receive the basemember 108. For example, the tool 404 has a plurality of, e.g., three,radial projections 406 to create channels radiating from the well asshown in FIG. 10D. Preferably the projections 406 have an edge profilesimilar to that of the arms 128, e.g., with a convex edge from proximalto distal when viewed from the side similar to the edge 210.

FIG. 10D show the expose humeral face F with the pin 400 and tool 404removed so that a created recess CR in the face F is shown. The recessCR is configured to permit the base 108 to be advanced with ease intothe face F of the humeral head h as shown in FIG. 10E. Morespecifically, the recess CR is shaped to match the shape of a portion ofthe base member 108 that projects distally. For example, FIG. 4 showsthat the arms 128 can be equally spaced about the base member 108, e.g.,outer ends thereof coupled with the peripheral member 140 can be spacedcircumferentially by about 120 degrees. The arms 128 can be thin atradially outer portions thereof and can be joined adjacent to the distalend 120 of the base member 108. Accordingly, the radial projections ofthe recess CR created by the radial projections 406 of the tool 404 canbe narrow and spaced apart by the same amount as the arms 128, e.g.,about 120 degrees apart.

Although the projection 406 and corresponding projections of the recessCR are generally straight, radial projections, the projections 406 couldbe curved and/or can extend away from a central region to in anon-radial direction matching the shape and orientation of anyprojections of the base member 108.

Preferably, the insertion of the base member 108 into the recess CR canbe achieved with ease, e.g., without an impactor or any other tools, butrather by hand force. The base member 108 advantageously is symmetricalabout the axis A (see FIGS. 4 and 5). This allows the surgeon to insertthe base member 108 in any orientation provided that the arms 128 andthe projections in the recess CR are aligned. Other configurations havea preferred orientation, as discussed further below.

FIGS. 10E-10F show that the countersunk region CS is configured toreceive the peripheral member 140 in a recessed position. For example,the countersunk region CS has a bone recessed area, which is recessed byabout the proximal-distal dimension 416 (shown in FIG. 6) of theperipheral member 140. By recessing the base member 108, the base memberand/or the humeral shoulder assembly 100 can positioned as desiredrelative to the face F of the humeral head h, e.g., with a small gap orflush mounted. Flush-mount enables a joint interface coupled with theassembly 100 to be positioned close to the face F, e.g., with little tono gap therein. Consistent and accurate positioning of the assembly 100and joint interface can be important factors in properly locating theprosthetic joint interface.

FIG. 10F shows that after the base member 108 has been inserted into theface F of the humerus a subsequent step can involve coupling the guidetool 432 with the base member. FIG. 25 shows details of one embodimentof the guide tool 432. The guide tool 432 preferably includes a guidebody 436 disposed at a proximal portion thereof. The guide body 436projects outside and proximally of the base member 108 and is configuredto guide the anchor member 112 to be advanced thereover. In one form,the guide body 436 is a cylindrical member. A distal portion 440 of theguide tool 432 is configured to be coupled with the base member 108. Inparticular, a threaded distal portion 444 is configured to mate with thethreads in the threaded recess 250 (see FIG. 6A). A tapered portion 448facilitates insertion of the guide tool 432 into the cylindrical member130 of the base member 108. More particularly as shown in FIG. 6A, thecylindrical member 130 can be tapered on an inside surface thereof, suchthat the recess formed in the member 130 is narrower at the distal endthan at the proximal end thereof. Stated another way, a wall surroundingthe recess in the cylindrical member 130 is closer to the axis A nearthe threads 250 than near the proximal end of the recess. Similarly, theoutside surface of the tapered portion 448 is closer to a centrallongitudinal axis B of the guide tool 432 than is a proximal portion ofthe tapered portion 448. The tapers match such that if the guide tool432 is inserted into the cylindrical member 130 with the axis A, Boffset, the surface 448 and the inside surface of the recess in thecylindrical member 130 match to align these axes before the threads 444and the threads in the recess 250.

FIG. 10G shows the anchor member 112 engaged with the base member 108.This configuration results from advancement of the anchor member 112over the guide tool 432 in one method. In one embodiment, a method stepincludes coupling a driver with the driver interface 364 on the proximalface 300 of the anchor member 112. The driver can take any suitableform, e.g., can include a plurality of protrusions configured to matewith recesses of the driver interface 364. The driver can be configuredto snap into or onto the anchor member 112 at the driver interface 364.Embodiments of a driver are discussed below in connection with FIGS. 16Band 24B. Preferably, the driver has a ratchet mechanism such that thesurgeon can continuously hold the tool and need not release the handleto re-grip it to apply additional turns to the anchor member 112.However, one advantage of the three thread design of the anchor member112 is that less rotation of the anchor member is required as comparedto a two thread design or a one thread design to fully seat the anchormember in the base member 108.

In one method, the surgeon observes the face F of the humerus andadvances the anchor member 112 until some fluid is observed to emergefrom the recess CR and/or around the assembly 100. The emergence offluid suggests that the anchor member 112 is fully seated in the bone ina way providing excellent initial bone retention. Such retentionprovides enhanced pull-out force.

FIG. 26 illustrates the initial pull-out force 1510 for Embodiment A, avariant of the shoulder assembly 100 in which the anchor member 112 hasa single continuous thread. Portions of the helical structure 304project into the open area defined between the arms 128 and engage thebone thereby increasing the initial pull-out force of the assembly 100when initially placed. As shown in FIG. 26, the peak force correspondingto the initial pull out force 1510 of Embodiment A is at least ten timesgreater than the peak force corresponding to the initial pull out force1500 of the prior art design having a base member and no anchor thread.

As discussed above, the assembly 100 enables a variety of jointinterface components. The surgeon can couple an anatomical jointinterface with the assembly 100, e.g., by positioning an anchor portionof the anatomical joint interface in the recess 104. In some cases, areverse shoulder configuration is better for the patient. The surgeoncan dispose an anchor portion of a reverse configuration shoulder jointinterface in the recess 104. FIG. 10H shows an adaptor 464 coupled withthe recess 104. The adaptor 464 can be seated with a concave socketportion 468 that can be coupled with a convex head implanted in thescapula in the reverse shoulder configuration.

The methods described above, e.g., in connection with FIGS. 10A-10H, caninclude additional steps and employ additional tools as discussed below.The shoulder assembly 100 also can be adapted to be compatible withother methods herein, e.g., having a guidewire passage suitable foremploying over-the-wire methods discussed below.

The assembly 100 and the methods described above can be modified byincorporation of structures and methods discussed in connection with theembodiments below.

II. Assemblies Having Guidewire Delivery Capability

FIG. 11-16C show a stemless shoulder assembly 500 and methods similar tothe shoulder assembly 100 and methods discussed above except asdescribed differently below. The assembly 500 is configured to allow aguidewire to be used to advance components thereof into a preparedhumeral face F, providing for an efficient and accurate procedure. Theassembly 500 includes a recess 504, a base member 508, and an anchormember 512. As discussed more below, a thread or other helicalprotrusion 532 extends from the anchor member 512 into engagement withthe base member 508 and into an open area where it can engage bone. Inthis embodiment, the anchor member 512 has a single lead configuration.Other embodiments can have a multiple lead configuration, e.g.,including a double lead, a triple lead, or a quadruple leadconfiguration.

FIGS. 12, 13 and 13A show features of the base member 508 thatfacilitate delivery of the base member and/or the anchor member 512 overa guidewire. For example, the base member 508 has a plurality of arms528A, 528B, 528C that extend between a distal and a proximal end 520,524 of the base member 508. The arms 528A, B, C are coupled with asleeve 530 disposed adjacent to the distal end 520 of the base member508. The sleeve 530 has an opening at a proximal end 534 thereofextending into a lumen 538. The lumen 538 extends from the opening atthe proximal end 534 to an opening at the distal end 520 of the sleeve530. The lumen 538 is accessible through an open space 542 disposedbetween the arms 528A, B, C and between the proximal end 534 of thesleeve 530 and the proximal end 524 of the base member 508. The space542 provides access to the lumen 538 by a direct path, e.g., a pathperpendicular to the plane of the proximal end 524 of the base member508.

FIG. 12 shows that the base member 508 includes a guide surface 548 anda lead surface 552 in some embodiments. The guide and lead surfaces 548,552 can be regions of a continuous guide member and can be a continuousexpanse without a change in orientation between them. The guide surface548 can be substantially flat, e.g., disposed on a plane that isperpendicular to a longitudinal axis C of the lumen 538. The leadsurface 552 can be angled to match the pitch of the helical protrusion532 (see FIG. 14) on the anchor member 512. The guide member or theguide and lead surfaces 548, 552 can be disposed adjacent to a peripheryof the base member 508, e.g., between a peripheral member 540 and theaxis C. In one embodiment, the guide and lead surfaces 548, 552 arecoupled at outer edges thereof with an inner edge of the peripheralmember 540. In one embodiment, a circumferential gap 544 is providedbetween ends of the guide and lead surfaces 548, 552. The gap 544 isconfigured to permit the helical protrusion 532 (see FIG. 14) to beadvanced along the lead surface 548 to a top laterally extending surface560A of the first arm 528A, which is disposed beneath the gap 544.

FIG. 13A show the path from the lead surface 552 to the top surface 560Athrough the gap 544 is a first segment of a helical path about the axisC. A second segment of the helical path extends from the top laterallyextending surface 560A to a top laterally extending surface 560B on thearm 528B. A third segment of the path extends from the top laterallyextending surface 560B to a top laterally extending surface 560C of thearm 528C. A fourth segment of the path extends from the top laterallyextending surface 560C to a laterally extending surface 564A of the arm528A below the surface 560A. The laterally extending surface 564A is amid-level surface on the arm 528A. The helical path through the base 508extends in the same manner across a plurality of mid-level surfacecorresponding to the surface 564A and a plurality of surfaces at a lowerlevel of the arms to a distal end point on or adjacent to or at alaterally extending surface 568C. The helical path described aboveaccommodates a single helical protrusion, e.g., thread, of the anchormember 512. An advantage of this design is that only a single threadmust traverse a gap in the proximal surface of the base portion 508.Also, the thread is much longer than the thread of the anchor member 112and is generally at a shallower angle and so may be advanceable alongthe helical path with less torque than is required for the anchor member112.

FIGS. 14 and 15 show further details of the anchor member 512. Inparticular, the anchor member 512 has a proximal face 600 having atapered annular surface. The proximal face 600 can include a driverinterface 604 that can take any suitable form, such as any of thosedescribed above. For example, driver interface 604 can include aplurality of recesses. FIG. 15 shows that the recess 504 can extend fromthe proximal face 600 to a distal end having an aperture 608 formedtherein. The aperture 608 can be configured to receive a guidewire suchthat the anchor member 512 can be advanced over a wire, as discussedfurther below.

FIGS. 16A-C illustrate various methods of implanting the shoulderassembly 500. The method can include compatible steps of any of themethods discussed above in connection with FIGS. 10A-10H, includinginitial preparation of a humeral head with a recess to receive aguidewire 650. The guidewire 650 can take any suitable form and issometimes known as a Kirschner wire or K-wire. The guidewire 650 isplaced into a recess extending distally into a face of a humeral head.Once in place, the base member 508 is advanced over the proximal end 654of the guidewire 650, e.g., an opening at the distal end of the lumen538 is advanced over the proximal end 654 of the guidewire 650. Thelumen 538 is sized so that the base member 508 can easily slide alongthe length of the guidewire 650 to a position corresponding to theposition of the base member 108 in FIG. 10E.

Thereafter, the base member 508 is advanced into the bone. For example,if a recess have been formed that has a profile similar to that of thebase member 508, the base member can be urged into the recess with lowforce, e.g., with hand force and without impactors or with light forcefrom the impactor. In some methods, the gap 544 is oriented with respectto the anatomy. For example, the gap 544 can be disposed at a lowerelevation (caudad) compared to the position of the guide surface 548.

FIG. 16B illustrates further step in which a cannulated driver 662 isadvanced over the guidewire 650. The cannulated driver 662 preferablyhas an interface configured to mate with the driver interface 604 on theanchor member 512. The driver 662 can have a plurality of prongsextending distally therefrom to engage recesses in the face 600 of theanchor member 512. In one step, the surgeon couples the driver 662 withthe anchor member 512. Once so coupled, the driver 662 and the anchormember 512 are advanced over the guidewire 650. An initial step ofadvancing the driver 662 and the anchor member 512 over the guidewire650 includes inserting the proximal end 654 of the guidewire 650 intothe aperture 608 in the anchor member 512. Continued advancement of thedriver 662 and the anchor member 512 causes the guidewire 650 to beadvanced through the driver 662 and out of a proximal end 668 thereof.

Once the driver 662 and the anchor member 512 are adjacent to theproximal portion of the base member 508, the distal portion of thehelical protrusion 532 is placed against the guide surface 548 and/orthe lead surface 552 and through the gap 544 and from there along thehelical path discussed above. Once fully advanced, the cannulated driver662 can be removed leaving the shoulder assembly 500 in place as shownin FIG. 16C. Thereafter the guidewire 650 is removed to allow subsequentsteps to proceed, including attachment of a joint interface as discussedabove.

Among the additional advantages of the shoulder assembly 500 isproviding a single sleeve-like structure in the anchor member 512 ratherthan co-axial sleeve one in each of the base and anchor members. Inparticular, in the assembly 500 only the anchor member 512 includes acylindrical structure. The cylindrical structure of the assembly 500reinforces the helical protrusion 532 and also comprises the recess 504.This provides a simpler construction having fewer components. Also,there is no chance for multiple cylinders to be slid over each other tobecome misaligned, leading to binding or increased torque requirementsfor advancing the anchor member 512 into the base member 508.

III. Assemblies Having Reinforced Base Members

FIGS. 17-24B illustrate an embodiment of a humeral shoulder assembly1000 in which distally projecting arms are more rigid by virtue of beingcoupled to each other and directly to a cylinder member at intermediatepositions. This structure retains the direct bone engagement of exposedthreads while making the arms more rigid.

FIG. 17 illustrates the assembly 1000 having a base member 1008 and ananchor member 1012. The base member 1008 and the anchor member 1012 areseparable components that can be applied to the patient separately,e.g., assembled in multiple steps within the bone in techniques similarto those discussed above.

FIGS. 18-22 illustrate various views of the base member 1008. The basemember 1008 has a distal end 1020 configured to be embedded in bone anda proximal portion 1024 to be disposed adjacent to the face F of thehumerus H or another bone surface.

As shown in FIG. 20, the base member 1008 can have a plurality of spacedapart arms 1028 projecting from the proximal portion 1024 to the distalend 1020 of the base member 1008. Each arm 1028 can define an outer edge1210 having an arcuate sloping surface. The sloping surface canfacilitate insertion of the base member 1008 into an exposed humeralface F as discussed above in connection with FIGS. 10A-10H. Further,each arm can define an inner edge 1214. The inner edge 1214 of a distalportion 1046 of each of the arms can be connected to form the distal end1020 of the base member 1008 (see FIG. 21).

The inner edge 1214 of each arm 1208 can include one or more laterallyextending recesses 1218A, 1218B, 1218C. The number of laterallyextending recesses can vary between different arms 1028. For example, asshown in FIG. 20, a first arm can include a first recess 1218A and asecond recess 1218B, while a second arm can include only one recess1218C. The recesses 1218A, 1218B of the first arm can be longitudinallydisplaced from the recess 1218C of the second arm to accommodate ahelical structure 1304 of the anchor member 1012 (see FIG. 17).Additionally, the outermost edge of each of the laterally extendingrecesses 1218A, 1218B, 1218C can be equidistant from the longitudinalaxis of the base member 1008 to accommodate an anchor member 1012 havinga substantially constant outer diameter along the helical structure 1304(see FIG. 17).

The base member 1008 can also include a central portion (e.g., acylindrical member 1030). As shown in FIG. 22, the cylindrical member1030 can include an open proximal end 1034 and a closed distal end 1032.The proximal end 1034 can define the proximal-most point of the basemember 1008. In certain aspects, the proximal end 1034 can include anannular groove 1076 (FIG. 18) for receiving a c-ring that may be presentto prevent loosening between the anchor member 1012 and the base member1008. A c-ring can be part of a locking device, as discussed further inconnection with FIGS. 27-27A below. Further, a threaded recess 1250 canbe formed in the distal portion of the cylindrical member 1030. Thethreaded recess 1250 enables a component to be advanced into a secureposition of engagement with the base 1008. The component can be part ofa prosthetic joint interface or can be a tool used in placement of theshoulder assembly 1000. For example, as shown in FIG. 24A, the recess1250 can engage a guide tool 432 (FIG. 25). The guide tool 432 canextend the length of the cylindrical member 1030 to facilitate insertionof the anchor member 1012 into the base member 1008.

FIG. 20 shows that the outer wall of the cylindrical member 1030 candefine a helical channel 1050 (e.g., groove or opening). The outer wallof the cylindrical member 1030 can connect to the inner edge 1214 of thearms 1028, such that portions of the helical channel 1050 can align witheach of the laterally extending recesses 1218A, 1218B, 1218C to form apathway for the helical structure 1304 of the anchor member 1112 (seeFIG. 17).

FIG. 19 illustrates that the proximal portion 1024 of the base member1008 can include a peripheral member 1040 disposed about the outerperiphery of the proximal portion 1024. The peripheral member 1040 canbe coupled with the proximal ends of the arms 1028 (see FIG. 22) toprovide a unitary structure. As shown in FIG. 19, the proximal portion1024 can include a guide member 1048 that can be connected to theperipheral member 1040. The guide member 1048 can be partially recessedfrom the proximal face of the peripheral member 1040 to provide a spaceinto which a proximal disc structure 1312 of the anchor member 1012 canbe positioned (see FIG. 17). Further, the guide member 1048 can includea plate-like projection extending radially inwardly from the peripheralmember 1040 to a proximal portion of the cylindrical member 1030. Forinstance, the guide member 1048 can extend continuously from the inneredge of the peripheral member 1040 to the cylindrical member 1030 aroundat least about 50% of an inner diameter of the peripheral member 1040.In an arcuate segment, the guide member 1048 can extend discontinuouslyfrom the inner edge of the peripheral member 1040 to the cylindricalmember 1030. For example, a gap 1072 can be defined adjacent to butradially inward of an arcuate segment of the guide member 1048 that isdisposed between the peripheral portion 1040 and the gap 1072. The gap1072 facilitates insertion of the anchor member 1012 into the basemember 1008.

As shown in FIG. 20, the proximal end 1034 of the cylindrical member1030 can be elevated above the proximal-most aspect of the peripheralmember 1040. When the anchor member 1012 is connected to the base member1008 (see FIG. 17), the proximal disc structure 1312 can fill theannular space bounded by the outside surface of the cylindrical member1030 and the inside surface of the peripheral member 1040 to create atapered, annular surface from proximal end 1034 of the cylindricalmember 1030 to the peripheral member 1040. This structure avoidsinflection points in the side profile of the assembly 1000, which isadvantageous in reducing or eliminating gaps between the assembly 1000and another component of a shoulder joint assembly coupled therewith.

FIG. 23 illustrates features of the anchor member 1012, which has aproximal disc structure 1312. The proximal disc structure 1312 candefine a central opening 1316 that can surround the proximal end 1034 ofthe cylindrical member 1030 when the shoulder assembly 1000 isassembled. Further, the proximal disc structure 1312 can include adriver interface 1364 (e.g. a plurality of openings) for engaging adriving tool 450 (see FIG. 24B). Rotating the driving tool 450 canadvance the anchor member 1012 to rotationally engage the base member1008.

The anchor member 1012 can also include a continuous helical structure1304 disposed distally of the proximal disc structure 1312. In thisembodiment, the anchor member 1012 has a single helical structure 1304.Other embodiments can have a multiple helices, e.g., including a doublehelix, a triple helix, or a quadruple helix configuration. The inneredge of the helical structure 1304 can define the innermost edge of theanchor member 1012 distal of the disc structure 1312 in that the anchormember 1012 does not include a central body structure. In at least thissense, the anchor member 1012 has an open helix construction. Thehelical structure 1304 defines a substantially constant inner diameterand a substantially constant outer diameter in one embodiment.

When the shoulder assembly 1000 is assembled, the disc structure 1312can abut the guide member 1048 of the base member 1008 and the helicalstructure 1304 can be disposed in the helical groove 1350 and thelaterally extending recesses 1218A, 1218B, 1218C of the base member 1008(see FIG. 17). Portions of the helical structure 1304 project into theopen area defined between the arms 1208 and engage the bone, therebyincreasing the initial pull-out force of the assembly 1000 wheninitially placed. As shown in FIG. 26, the peak force corresponding tothe initial pull out force 1520 of the shoulder assembly 1000 is atleast five times greater than the peak force corresponding to theinitial pull out force 1500 of the prior art.

FIGS. 24A-24B illustrate tools that can be used to implant the shoulderassembly 1000 and corresponding methods. The method of using the toolscan include compatible steps of any of the methods discussed above inconnection with FIGS. 10A-10H including creating a recess CR in thehumeral head (see FIG. 10D). Once the recess CR is created, the basemember 1008 can be inserted into the face F of the humerus head h(similar to FIG. 10E). Preferably, the insertion of the base member 1008can be achieved without an impactor or any other tools, but rather justinserted by hand force.

After the base member 108 has been inserted into the recess CR, asubsequent step can involve coupling the guide tool 432 with the basemember 1008 (see FIG. 24A). As described above, FIG. 25 illustrates oneembodiment of the guide tool 432. The guide tool 432 can extend thelength of the cylindrical member 1030 to guide the anchor member 1112into the base member 1008. To advance the anchor member 1012 over theguide tool 432, the method can include coupling a driver 450 with thedriver interface 1364 (see FIG. 24B). The driver 450 can take anysuitable form, e.g., can include a plurality of protrusions configuredto mate with openings of the driver interface 1364. Preferably, thedriver 450 has a ratchet mechanism such that the surgeon cancontinuously hold the tool and need not release the handle to re-gripit. Once the shoulder assembly 1000 is assembled, the driver 450 and theguide tool 432 can be removed.

The methods described above, e.g., in connection with FIGS. 24A-24B, caninclude additional steps and employ additional tools as discussed above.The shoulder assembly 1000 and/or the tool 450 also can be adapted to becompatible with other methods, e.g., with over-the-wire methods. Forinstance, the base member 1008 can have a lumen extending through thedistal end 1020 to guide the base member into place. A channel in thetool 450 can be used in guiding the anchor member 1012 into place in thebase member 1008.

IV. Locking Devices to Reduce or Eliminate Disengagement of Base andAnchor Members

FIGS. 27-32 show features that can reduce or eliminate disengagementbetween a base member and an anchor member. These embodiments areillustrated in connection with the shoulder assembly 100, but can beused in connection with any of the embodiments herein. Also, althoughthe features are discussed separately they could be combined in someembodiments.

FIGS. 27 and 27A shows a shoulder assembly 1100 that includes a basemember 1108, an anchor member 1112, and a locking device 1118 disposedadjacent to a proximal end 1124 of the base member 1108. The lockingdevice 1118 comprises a C-ring 1122 that is disposed partially in arecess or groove 1126 (See FIG. 27A) of the anchor member 1112 andpartially in a groove 1130 (see FIG. 27A) of the base member 1108. FIG.28 shows a partial assembly in which the C-ring 1122 is coupled with theanchor member 1112 prior to coupling the anchor member 1112 to the basemember 1108. In the illustrated embodiment, the C-ring 1122 is disposedin the anchor member 1112 prior to implantation. FIG. 27A shows that thecross-sectional shape of the C-ring 1122 facilitates actuation of theC-ring 1122 during assembly. A distal face 1134 of the C-ring 1122 isangled relative to a plane oriented perpendicular to the distal-proximaldirection of the assembly 1100. In assembly, the anchor member 1112 isadvanced into the base member 1108 until the distal face 1134 engages aproximal portion 1138 (See FIG. 27A) of the base member 1108 and isdeflected thereby into or deeper into the recess 1126 of the anchormember 1112. This permits the anchor member 1112 to move relative to thebase member 1108 until the C-ring 1122 moves to the position of thegroove 1130. The resilience of the C-ring 1122 causes the C-ring toreturn to an un-deflected configuration thereof. FIG. 27A shows thefinal position of the C-ring 1122 with a portion disposed in the groove1130 and a portion disposed in the groove 1126. In this configuration,the anchor member 1112 is locked into the base member 1108 becausefurther advancement of the anchor member 1112 into the base member 1108is prevented by contact between a base face 1148 and an anchor face 1120and because retraction of the anchor member 1112 from the base member1108 is prevented by the C-ring 1122 in cooperation with grooves 1126and 1130 (see FIG. 27).

In other embodiments, the C-ring 1122 can be coupled with the basemember 1108 prior to assembly of the anchor member 1112 with the basemember 1108. In such embodiments, a surface of the anchor member 1112can be configured to deflect the C-ring 1122 into or deeper into thegroove 1130. In such embodiments, a proximal face of the C-ring 1122 maybe angled relative to a plane oriented perpendicular to thedistal-proximal direction of the assembly to facilitate deflection ofthe C-ring. Although a C-ring is illustrated, other structures that canbe temporarily deflected into the recess 1126 or the recess 1130 can beused, such as spring loaded or resilient detents or members or othersimilar structures.

FIGS. 29 and 30 illustrate another embodiment of a shoulder assembly1200 that has a base member 1208, an anchor member 1212, and a lockingdevice 1218 comprising an interface between the anchor member 1212 andthe base member 1208. The locking device 1218 includes a distalprojection 1220 disposed on a distal side of a helical protrusion 1232(see FIG. 30). FIG. 30 shows that the distal projection 1220 can have afirst face 1222 that is oriented generally proximal to distal and asecond face 1226 that is disposed at an angle relative to a planeextending perpendicular to the proximal-distal direction of the anchormember 1212.

In use, the anchor member 1212 is advanced into the base member 1208 inthe same manner as described above in connection with the assembly 100.As the anchor member 1212 approaches the fully engaged position, thesecond face 1226 of the projection 1220 approaches a first side 1228A ofthe arm 1228 of the base member 1208. The second face 1226 passes acrossa lower lateral face of an upper-most slot of the arm 1228. As thesecond face 1226 crosses the arm 1228 from the first side 1228A, localdeformation of at least one of the arm 1228 and the projection 1220permits further advancement of the second surface 1226 relative to thearm until the first surface is disposed on the second side 1228B of thearm 1228 (see FIG. 29). The local deformation is preferably temporarysuch that the deformed structure(s) return toward their undeformedstate(s). Once disposed on the second side 1228B of the arm 1228, thefirst face 1222 abuts a corresponding surface of the second side 1228Bof the arm 1228. In this configuration, the anchor member 1212 is lockedinto the base member 1208 because further advancement of the anchormember 1212 into the base member 1208 is prevented by contact between anupper surface of the base member 1208 and an anchor face 1224 andbecause retraction of the anchor member 1212 from the base member 1208is prevented by contact between the first face 1222 and the second side1228B of the arm 1228.

The locking device 1218 is simple in construction in that a firstportion of the interface is disposed on the anchor member 1212 and asecond portion of the interface is disposed on the base member 1208 andthus does not require another separable component compared to theshoulder assembly 1100. Also, the locking device 1218 does not requirean additional discrete step in the locking of the base member 1208 tothe anchor member 1212 because the final step of passing the projection1220 from the first side 1228A to the second side 1222B is accomplishedwith the same rotation as is required in connection with the assembly100, though some additional force may be required to provide the localdeformation discussed above.

FIGS. 31 and 32 show another embodiment of a shoulder assembly 1300 thathas a base member 1308, an anchor member 1312, and a locking device 1318comprising at least one, e.g., a plurality of deflectable prongs 1320that can be deployed to span from one of the anchor member 1312 and thebase member 1308 to the other of the anchor and base members. Thespanning of the prong(s) 1320 causes a portion of the prong to beengaged with the base member 1308 and another portion to be engaged withthe rotatable anchor member 1312 such that rotation of the anchor memberin either direction is reduced or eliminated.

FIG. 31 shows that the prongs 1320 can be disposed on the anchor member1312 about an inner periphery 1332 of a disc structure 1336 thereof. Thebase member 1308 can have a cylindrical member 1324, similar to thatdiscussed above in connection with the assembly 100. The cylindricalmember 1324 can have a plurality of scallops or recesses 1328 disposedon a side surface thereof. The recesses 1328 can extend entirely aroundthe cylindrical member 1324 in one embodiment to enable the prong(s)1320 to be engaged at a nearest recess 1328 rather than come preciselyto rest at a specific rotational position and recess. In otherembodiments, the base and anchor members 1308, 1312 could be providedwith the same number or prongs and recesses, wherein the location of theprongs and recesses are provided at an expected fully engaged positionof the anchor member 1312 relative to the base member 1308.

FIG. 31 shows the prong(s) 1320 in a disengaged position. Any suitabletechnique or tool can be used to deploy the prongs 1320 across a gapbetween the anchor member 1312 and the base member 1308. FIG. 32illustrates a tool 1400 that can be used to deploy the prongs 1320. Thetool 1400 includes a proximal user grip portion 1404, which can be acylindrical member or any other ergonomic gripping structure. The tool1400 also includes a plurality of pins 1408 disposed on a distal portionthereof that are configured and positioned to engage driver interfaces1364 disposed on the proximal face of the disc structure 1336. The pins1408 can be on an opposite side of the tool 1400 from the grip portion1404. The tool 1400 also includes a plurality of prong actuators 1412disposed on the same side of the tool as are the pins 1408. The prongactuators 1412 can each include a first, radially inward side 1416 and asecond, radially outward side 1420. An angled surface 1424 is disposedbetween the sides 1416, 1420. The angled surface 1424 is configured toengage the prongs 1320 and deflect and in some cases deform them as thetool 1400 is advanced. For example, the radially outward side 1420 isconfigured and positioned to be inserted into a recess 1340 disposed inthe proximal faces of the disc 1336 radially outward of the prongs 1320.This initial insertion of the prong actuator 1412 into the recess 1340can be up to a point where the angled surface 1424 first engages theprong 1320. The radial distance from the first, radially inward side1416 to the second, radially outward side 1420 is greater than theradial extent of the recess 1340. The radial distance from the first,radially inward side 1416 to the second, radially outward side 1420spans the recess 1340, the gap between the anchor and base members 1312,1308 and into the scallop or recess 1328. Further advancement of thetool 1400 causes the angled surface 1424 to engage the prong 1320. Stillfurther advancement of the tool 1400 causes the prong 1320 to bedeflected, e.g., bent or otherwise deformed into the recess 1328 of thebase member 1308. When so deflected, the prong 1320 spans from the discstructure 1336 of the anchor member 1312 to the recess 1328 of the basemember 1308. Because the base member 1308 is fixed in the bone, thecoupling of the prong 1320 with the base member 1308 causes the anchormember 1312 also to be fixed relative to the bone. This prevents anybacking out or unintended disengagement of the anchor member 1312 fromthe base member 1308.

As illustrated, one embodiment of the locking device 1318 comprises sixprongs 1320. In other embodiments, one prong 1320 can be provided. Inother embodiments, a plurality of prongs, e.g., two three, four, five,twenty, or more prongs 1320 can be provided. The prongs 1320 could bedisposed on the base member 1308 and could be deflected, e.g., bent orotherwise deformed, into a scallop or recess disposed on the anchormember 1312 in other embodiments. In further embodiments, the prong 1320can be configured as a spanning member that need not be formed as a partof either the base member 1308 or the anchor member 1312 but rather as aseparate components installed at the proximal side of the assembly 1300.As discussed above, the various locking devices discussed herein can becombined to provide multiple locking structures.

V. Anchor Members which Lock to Stems

As demonstrated above, the unique anchor and base members describedherein provide for excellent securement of joint implant to bone, e.g.,of humeral implants to a resected humerus. The excellent securementprovided by these implants is provided immediately after a procedurewithout the need to wait for bone ingrowth. FIGS. 33-35 illustrate ahumeral implant 1600 and components thereof. The humeral implant 1600includes a stem and that combines the securement benefits of a stem withthe securement benefits of the base and anchor member as discussedherein.

FIGS. 33 and 34 show the humeral implant 1600 includes a stem 1610. Theimplant 1600 also includes an anchor member 1612. As discussed furtherbelow, the anchor member 1612 is similar to other anchor membersdiscussed above. The description of the features of the other anchormembers discussed herein may be combined with or substituted for thefeatures of the anchor member 1612 described below.

The anchor member 1612 has a proximal face 1614 and a distal threadedportion 1618. The distal threaded portion 1618 can have a radially inneredge coupled with a cylindrical portion 1619 of the anchor member 1612.A radial outer edge and an expanse between the inner and outer edges ofthe threaded portion 1618 are adapted to be advanced into and then to beembedded in bone. The implant 1600 provides high confidence insecurement by combining the engagement between the threaded portion 1618and the bone matter in the metaphysis with engagement between the distalportion 1636 of the stem 1610 and the bone matter surrounding the canalof the humerus. In the event the engagement between the threaded portion1618 and the bone matter of the metaphysis is not sufficient, the stem1610 provides additional securement. See FIG. 26 and correspondingdiscussion for details of securement using such a threaded portion. Theproximal face 1614 can have a tool interface 1620 that can be engaged bya driver to advance the anchor member 1612 into or remove the anchormember from the stem 1610. FIG. 34 shows that the proximal face 1614 canbe flush with a proximal portion of the stem 1610 when fully advanced.That is, the face 1614 can be positioned so that it does not protrudeproximally of a proximal most aspect of the stem 1610, which isdiscussed further below. FIG. 33 shows that the proximal face 1614 canbe annular, providing an inner edge 1622 that allows access to a portionof the stem 1610 as discussed below. The inner edge 1622 can be disposedat the proximal end of the cylindrical portion 1619. In one embodiment,the cylindrical portion 1619 projects from the inner edge 1622. FIG. 33also shows that the proximal face 1614 includes an outer edge 1624 thatcan be received by and in some cases surrounded by an outer periphery ofa proximal portion of the stem 1610.

The stem 1610 is advantageous in providing multiple modes of securementto a bone, e.g., to a proximal humerus. Compared to the aforementionedstemless designs, the stem 1610 gives a surgeon an option in evaluatinga patient to be able to quickly adapt a surgical plan to an implantproviding more security or providing security to a different bonesegment, such as a canal which may be more robust than the cancellousbone disposed at or just beneath the resection plane. FIG. 35 shows thatthe stem 1610 includes a proximal portion 1632 and a distal portion1636. The distal portion 1636 is configured to be inserted throughcancellous bone, for example through a resected humerus of a patient. Adistal tip 1640 of the distal portion 1636 can be inserted to extendinto an intramedullary canal of the humerus. In some embodiments thedistal portion 1636 includes a central portion 1644 extending proximallyfrom the distal tip 1640, with one or more projections 1648 extendingaway from the central portion 1624. The projections 1648 can includetwo, three, four or more projections 1648. In some embodiments, theprojections 1648 are evenly spaced around the central portion 1644. Forexample, if there are three projections 1648, they may be spaced apartby 120 degrees. The projections 1648 enable the distal portion 1636 tobe inserted into the canal of a long bone, such as a humerus, along thinouter edges of the projections 1348 such that contact with the bone inthe canal is initially line contact. This makes insertion of the distalportion 1636 easier because there is less friction between the stem 1610and the bone. While this provides for relatively minimal surfacecontact, the anchor member 1612 provides excellent securement, asdiscussed further below.

The proximal portion 1632 includes a distal region that can have thesame or a similar form to that of a proximal region of the distalportion 1636. For example, the distal region of the proximal portion1632 can have a central portion 1652 and one or a plurality ofprojections 1656. The proximal portion 1632 also can have one or more,e.g., three, projections. In one use, the stem 1610 is configured suchthat when implanted in a long bone, e.g. in the humerus, the proximalportion 1632 is disposed in the metaphysis of the bone. That is, thebone may be resected and thereafter, the distal portion 1636 can beadvanced into the canal of the humerus, leaving the proximal portion1632 in the metaphysis.

The projections 1656 can include similar or the same features discussedabove in connection with the arms 128 projection from the proximal endof the anchor member 108. For example, the projections 1656 can includelateral spaces to receive and guide the threaded portion 1618 of theanchor member 1612 to the advanced position as shown in FIGS. 33 and 34.A gap also can be defined between the inner edges of the projections1656 and an outer surface of the central portion 1652. The gap canaccommodate the cylindrical portion 1619 of the anchor member 1612.

FIG. 33 shows that the stem 1610 of the implant 1600 includes aperipheral rim 1660 disposed about, e.g., surrounding the centralportion 1652. The central portion 1652 can include a cylindrical memberthat is similar to the cylindrical member 130 in some embodiments. Theperipheral rim 1660 preferably is coupled with each of the projections1656. The peripheral rim 1660 can be configured to provide structuralintegrity to the projections. The peripheral rim 1660 has a plurality oftool features 1664 disposed about the periphery. In one embodiment, thetool features 1664 include three features equally spaced about the rim.The features can be used to advance the stem 1610 distally into thehumerus after the humerus has been resected. In the event the stem 1610is to be explanted the tool features 1664 can be engaged to dislodge thestem from the humerus.

The stem 1610 also includes a recess 1666 in which an articularcomponent, such as a glenosphere, can be anchored. The recess 1666 issimilar to the recess 104 discussed above in certain embodiments. Therecess 1666 can be disposed in the central portion 1652. The centralportion 1652 can have a tapered inner surface to provide a Morse taperconnection with the articular component.

A method of implanting the implant 1600 can be similar to thosediscussed above. For example, the humerus can be resected at about thelevel of the metaphysis. Thereafter, access to the canal of the humeruscan be provided or confirmed. After the access has been provided, thestem 1610 can be advanced through the resected surface of the humerus.For example, the tip 1640 can be urged through the resection plane andthereafter deeper into the humerus and further into the humeral canal.As the stem 1610 is advanced the projections 1648 engage the canal andact to center the distal portion 1636 of the stem in the canal.Advancement can be over a wire (in which case stem 1610 can becannulated) as illustrated above in connection with FIGS. 16A-16C orfreehand. After the stem 1610 is situated in the bone such that theperipheral rim 1660 is about at the plane of the resection, the surgeoncan confirm placement. If appropriate, the surgeon may further advancethe stem by impacting the stem into the bone. After the stem 1610 isproperly placed, the anchor member 1612 can be advanced into theproximal portion 1632 of the stem as discussed above. For instance, atool can engage the features 1620 and then apply a torque to engage thethread start(s) of the anchor member 1612 with the thread guidingfeatures of the projections 1656. Full advancement of the anchor member1612 can be confirmed by a positive stop of the cylindrical portion 1619or by visible confirmation. The implant 1600 provides at least twoindependent modes or zones of securement. In one mode, the implant 1600is secured in the cancellous bone of the humerus at the methaphysis bythe threaded portion 1618 disposed within the proximal portion 1632 ofthe stem 1610. The proximal portion 1632 thus corresponds to one zone ofsecurement. This mode and zone of securement are similar to thatdiscussed above in connection with FIG. 26. A second mode of securementis provided by the distal portion 1636 of the stem 1610, wherein thestem can integrate with the bone matter surrounding the canal of thehumerus. The distal portion 1636 thus corresponds to another zone ofsecurement.

VI. Assemblies Having Porous Titanium Structures

FIGS. 36-37 illustrate embodiments in which one or more components areat least partially formed by additive manufacturing. In certain additivemanufacturing techniques a structure is assembled from components tocreate a three dimensional porous metal structure. The structure isformed by applying or creating individual layers that are later joinedtogether through a suitable process, such as sintering. The layers canbe laid down to progressively to form the three dimensional structure.FIG. 36 shows a humeral implant 1700 including a base member 1708, ananchor member 1712, and a humeral head 1714. In one embodiment, one ormore features of the anchor member 1712 are formed by a process ofadditive manufacturing. More specifically, the spaced apart arms orprojections 1728 of the anchor member 1708 and other structures thatinteract with the bone may be comprised of a unitary or monolithicporous titanium (Ti-6Al-4V). A bottom surface of a peripheral rim 1740can be formed by additive manufacturing. As a result, the arms 1728and/or the distal side of the rim 1740 can have a porous titaniumstructure that contacts a bone, e.g., a resected portion of the humerus.Porous titanium has a modulus similar to bone or of about 2.6 GPa.Matching the modulus of the porous titanium to the bone may enablebetter stress transfer from the implant to the bone, reducing wear onthe bone, and increasing strength at the bone/implant interface.

The porous titanium structure can have a pore size from about 300 toabout 800 μm, in embodiments from about 350 to about 750 μm, and infurther embodiments from about 400 to about 700 μm. The porosity of theporous titanium structure may be optimized per implant geometry andanatomy and can be about 50%, 55%, 60%, 65%, 70%, 75%, and 80% porous.

Porous titanium can be formed by an additive manufacturing process,including a 3 dimensionally (3-D) printing process where layers oftitanium are formed to create a three dimensional structure. The initiallayer or layers are formed by such a method directly onto a portion orsurface of the anchor member 1708. The 3-D printing process includesdirect metal laser sintering onto the implant, more specifically, theanchor member 1708. First, blanks are formed by sintering titaniumpowder with a laser directly onto the substrate or anchor member. Next,in some techniques the blanks are machined, constructed or shaped tocreate a specific geometry of the bone-engaging surface. In someembodiments, the blanks are shaped to create either a stemless implant(as in FIG. 36) or an implant with a stem that can couple with theanchor member discussed herein (as in FIG. 37). Although the 3-D processis used herein to create stemmed or stemless members for implantation inthe metaphysis and/or the canal of the humerus, other portions andsurfaces of the implants may be formed with porous titanium, and arewithin the scope of this disclosure, including, but not limited to theanchor member or peripheral screws or portions thereof, central posts,and other structures that may be combined therewith. Once constructed,the porous structure and the solid substrate of baseplate comprise amonolithic, or one-piece structure. Alternatively, Electron Beam Melting(EBM) can be used to 3-D print a porous three dimensional structure onthe implant.

FIG. 37 shows a humeral implant 1800 that is a modified embodiment ofthe humeral implant 1600. The implant 1800 includes an anchor member1812 and a stem 1810. The stem 1810 includes a porous substrate 1814that is disposed over a portion thereof. In one embodiment, the poroussubstrate is formed by additive manufacturing, e.g., 3-D printing asdiscussed above. The porous substrate 1814 can extend over a proximalportion of the stem 1810. For example, the porous substrate can bedisposed over the metaphyseal bone contacting surfaces of the portion ofthe base not embedded in a canal of the humerus in use. The proximalportion that is porous titanium can include some or all of a pluralityof projections 1856. The proximal portion that is porous titanium alsocan include some or all of a peripheral rim 1860, e.g., a distal boneengaging side of the rim 1860. The porous titanium substrate can alsoextend distally of the projections 1856 to a location at or just distalof the narrowing of the metaphysis.

In one embodiment, a kit is provided that includes a stemless humeralimplant, such as the humeral shoulder assembly 100, and a stemmedhumeral implant such as the implant 1600 or the implant 1800. Byproviding these components together in a kit a clinician can quicklyadapt during a procedure from a stemless approach to a stemmed approach.For example, if the bone is not strong enough to support a stemlessimplant, the stemmed implant can be used without significant delay oruse of much different components. In fact, the anchor member 112 couldbe used with either stem or stemless implants. Furthermore, some kitscan include a variety of sizes of one or both of the stemless implant orthe stemmed implant. For example, the base member 108 can come indifferent sizes to occupy an appropriate volume of the metaphysis of thespecific humerus that is being treated by the surgeon. In someembodiments, the stem 1610 or the stem 1810 can be provided in a numberof sizes such that the distal ends thereof reaches an appropriate depthin the canal of the humerus and/or fits in the canal with little or nopreparation of the bone around the canal.

As used herein, the relative terms “proximal” and “distal” shall bedefined from the perspective of the humeral shoulder assembly. Thus,distal refers the direction of the end of the humeral shoulder assemblyembedded in the humerus, while proximal refers to the direction of theend of the humeral shoulder assembly facing the glenoid cavity.

Conditional language, such as “can,” “could,” “might,” or “may,” unlessspecifically stated otherwise, or otherwise understood within thecontext as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements, and/or steps. Thus, such conditional language is notgenerally intended to imply that features, elements, and/or steps are inany way required for one or more embodiments or that one or moreembodiments necessarily include logic for deciding, with or without userinput or prompting, whether these features, elements, and/or steps areincluded or are to be performed in any particular embodiment.

The terms “approximately,” “about,” and “substantially” as used hereinrepresent an amount close to the stated amount that still performs adesired function or achieves a desired result. For example, the terms“approximately”, “about”, and “substantially” may refer to an amountthat is within less than 10% of, within less than 5% of, within lessthan 1% of, within less than 0.1% of, and within less than 0.01% of thestated amount. As another example, in certain embodiments, the terms“generally parallel” and “substantially parallel” refer to a value,amount, or characteristic that departs from exactly parallel by lessthan or equal to 15 degrees, 10 degrees, 5 degrees, 3 degrees, 1 degree,0.1 degree, or otherwise.

Some embodiments have been described in connection with the accompanyingdrawings. However, it should be understood that the figures are notdrawn to scale. Distances, angles, etc. are merely illustrative and donot necessarily bear an exact relationship to actual dimensions andlayout of the devices illustrated. Components can be added, removed,and/or rearranged. Further, the disclosure herein of any particularfeature, aspect, method, property, characteristic, quality, attribute,element, or the like in connection with various embodiments can be usedin all other embodiments set forth herein. Additionally, it will berecognized that any methods described herein may be practiced using anydevice suitable for performing the recited steps.

For purposes of this disclosure, certain aspects, advantages, and novelfeatures are described herein. It is to be understood that notnecessarily all such advantages may be achieved in accordance with anyparticular embodiment. Thus, for example, those skilled in the art willrecognize that the disclosure may be embodied or carried out in a mannerthat achieves one advantage or a group of advantages as taught hereinwithout necessarily achieving other advantages as may be taught orsuggested herein.

Although these inventions have been disclosed in the context of certainpreferred embodiments and examples, it will be understood by thoseskilled in the art that the present inventions extend beyond thespecifically disclosed embodiments to other alternative embodimentsand/or uses of the inventions and obvious modifications and equivalentsthereof. In addition, while several variations of the inventions havebeen shown and described in detail, other modifications, which arewithin the scope of these inventions, will be readily apparent to thoseof skill in the art based upon this disclosure. It is also contemplatedthat various combination or sub-combinations of the specific featuresand aspects of the embodiments may be made and still fall within thescope of the inventions. It should be understood that various featuresand aspects of the disclosed embodiments can be combined with orsubstituted for one another in order to form varying modes of thedisclosed inventions. Further, the actions of the disclosed processesand methods may be modified in any manner, including by reorderingactions and/or inserting additional actions and/or deleting actions.Thus, it is intended that the scope of at least some of the presentinventions herein disclosed should not be limited by the particulardisclosed embodiments described above. The limitations in the claims areto be interpreted broadly based on the language employed in the claimsand not limited to the examples described in the present specificationor during the prosecution of the application, which examples are to beconstrued as non-exclusive.

What is claimed is:
 1. A stemless humeral shoulder assembly, comprising:a mounting member of a shoulder joint articular interface component; anda base member including: a first end including a peripheral rim thatencircles the first end and an inner member having an outside surfaceand an inside surface, the inside surface including an inner peripheryof the base member, the inner member configured to receive andthereafter be located around an outside surface of the mounting memberwhen the mounting member is advanced into the inner member of the basemember; a second end configured to be embedded in a bone; at least oneflat surface extending between the peripheral rim and the inner member,the at least one flat surface disposed at an elevation distal of aproximal-most aspect of the peripheral rim; and a plurality of spacedapart arms extending radially outward of the outside surface of theinner member, each of the plurality of spaced apart arms including (i)an outer edge and first and second lateral surfaces extending from theouter edge toward the outside surface of the inner member, (ii) aplurality of openings extending through the first and second lateralsurfaces and open toward the outside surface of the inner member, and(iii) an inner edge spaced apart from the outside surface of the innermember, wherein the first and second lateral surfaces of each of theplurality of spaced apart arms are separated by a thickness, each of thefirst and second lateral surfaces extending from the second end of thebase member toward the first end of the base member, each of the firstand second lateral surfaces having a width measured in a radialdirection, the width of each of the first and second lateral surfacesbeing greater than the thickness.
 2. The stemless humeral shoulderassembly of claim 1, wherein in each of the plurality of spaced apartarms, the plurality of openings are spaced apart along a longitudinaldirection of a corresponding one of the each of the plurality of spacedapart arms.
 3. The stemless humeral shoulder assembly of claim 1,wherein in each of the plurality of spaced apart arms, the plurality ofopenings are a plurality of slots.
 4. The stemless humeral shoulderassembly of claim 1, wherein the plurality of spaced apart arms is threespaced apart arms.
 5. The stemless humeral shoulder assembly of claim 1,wherein each of the plurality of openings intersects a longitudinal axisof the respective one of the plurality of spaced apart arms.
 6. Thestemless humeral shoulder assembly of claim 1, wherein the mountingmember includes an anatomical joint interface configured to be receivedin the inner member.
 7. The stemless humeral shoulder assembly of claim1, wherein each of the plurality of spaced apart arms comprises a porousstructure.
 8. The stemless humeral shoulder assembly of claim 2, whereinthe plurality of spaced apart arms and the peripheral rim form amonolithic structure.
 9. The stemless humeral shoulder assembly of claim2, wherein the inner member projects from the first end of the basemember and through the second end of the base member.
 10. The stemlesshumeral shoulder assembly of claim 1, wherein the plurality of spacedapart arms comprises three spaced apart arms extending between the firstend and the second end of the monolithic base member, each of the threespaced apart arms comprising a porous structure.
 11. The stemlesshumeral shoulder assembly of claim 1, wherein each of the threeplurality of spaced apart arms comprises an arcuate outer edge.
 12. Thestemless humeral shoulder assembly of claim 1, wherein each of theplurality openings comprises a radially outer edge.
 13. The stemlesshumeral shoulder assembly of claim 12, wherein the radially outer edgesof the plurality of openings in each of the plurality of spaced apartarms are located at different distances from the inner edge of each ofthe plurality of spaced apart arms along a radial direction of each ofthe plurality of spaced apart arms.
 14. The stemless humeral shoulderassembly of claim 1, wherein the first end of the base member comprisesa plurality of arcuate openings.
 15. The stemless humeral shoulderassembly of claim 14, wherein each of the plurality of arcuate openingscomprises a first straight edge, a second straight edge, and an arcuateedge therebetween.
 16. A stemless humeral shoulder assembly, comprising:a mounting member of a shoulder joint articular interface component; anda stemless humeral bone coupler, comprising: a first end comprising: aperipheral rim that defines an outer circumference of the stemlesshumeral bone coupler; and an inner member having an outside surface andan inside surface that defines a recess sized and configured to receivethe mounting member; a second end configured to be embedded in humeralbone; a flat surface extending between the peripheral rim and the innermember, the at least one flat surface disposed at a distance distal of aproximal-most aspect of the peripheral rim; and a plurality of spacedapart arms extending radially outward of the inner member, each of theplurality of spaced apart arms comprising: an outer edge, an inner edge,and first and second lateral surfaces extending from the inner edgetoward the outer edge and extending from the second end of the basemember toward the first end of the base member, wherein the inner edgethat is spaced apart from the inner member such that an opening isdefined between the inner member and the inner edge, the openingextending from the first lateral face to the second lateral face,wherein the first and second lateral surfaces of each of the pluralityof spaced apart arms are separated by a thickness and have a widthextending from the inner edge toward the outer edge in a radialdirection, and wherein the width of each of the first and second lateralsurfaces is greater than the thickness.
 17. The stemless humeralshoulder assembly of claim 16, wherein the plurality of spaced apartarms includes four arms.
 18. The stemless humeral shoulder assembly ofclaim 16, wherein the inner member and the plurality of spaced apartarms comprise a unitary structure.
 19. The stemless humeral shoulderassembly of claim 18, the inner member and the plurality of spaced apartarms are configured to be advanced into the humeral bone.
 20. Thestemless humeral shoulder assembly of claim 16, wherein the inner memberis cylindrical.
 21. The stemless humeral shoulder assembly of claim 16,wherein at least the plurality of arms of the stemless humeral bonecoupler comprise a porous structure.
 22. The stemless humeral shoulderassembly of claim 21, wherein at least the plurality of arms of thestemless humeral bone coupler comprise titanium.
 23. A kit comprising:the stemless humeral shoulder assembly of claim 16; a pin configured toguide a reaming instrument; and a tool comprising radial projectionsconfigured to create channels in cancellous bone, each channelconfigured to receive one of the arms of the plurality of arms.